Jellyfish (C3/DS)

From Creatures Wikia

An underwater inhabitant of Aquatilis Caverna. Distantly related to the Pest Jellyfish, but uses the same propulsion system. Unlike its counterpart, it is perfectly harmless. Its diet only consists of Shrimp, balancing the other species' population. Wanders aimlessly. It is quite tough, as it can adapt to any temperature in its environment. Though they can give birth, they are not mammals, but actually another category altogether, which makes them unique.

...quite possible these were created by the same Precursors who wrote those symbols on the walls, and created the Knowledge Stone. But this is all speculation, they could be just evolved from prehistoric jellyfish. Who knows? -From the diaries of Terasumaren.